<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        //成绩统计：作业练习
        var num = prompt('请输入班级的总人数:');//num 总的班级人数
        var sum = 0;//求和的变量
        var average = 0 ;//求平均值的变量
        for(var i = 1; i <=num; i++){
            var score = prompt('请您输入第'+i+'个学生成绩');
            //因为从prompt取过来的数据是 字符串型的需要转换为数字型
            sum=sum+ parseFloat(score);
        }
        average = sum /num;
        alert ('班级总的成绩是'+sum);
        alert('班级平均分是:'+average);
    </script>
</head>
<body>
    
</body>
</html>